" A portmanteau is a word whose form and meaning are a blend of the forms and meanings of two other words. That’s a stuffy explanation for a fun class of words: consider “smog,” a blend of “smoke” and “fog,” or “brunch,” a blend of “breakfast” and “lunch.” “Portmanteau” is itself a portmanteau: it’s the medieval French word for a large suitcase and is a blend of porter (“ to carry”) and manteau (“ mantle, cloak”). "

― Kory Stamper , Word by Word: The Secret Life of Dictionaries